Interpretive Summary: There is a scarcity of basic information on how physiological, horticultural, environmental, entomological and pathological variables affect subtropical/tropical fruit production systems and how these interact to influence yield and fruit quality. Development of efficient and sustainable management systems as well as identification of superior clones yielding high quality fruits are of paramount importance to ensure the success and sustained production of the emerging tropical fruit industry in the U.S. Therefore, germplasm collections need to be characterized and accessions evaluated as an avenue to identify high yielding clones with better fruit quality traits and/or with pest and disease resistance. Research projects housed at the USDA-ARS, Tropical Agriculture Research Station (TARS) in Mayaguez, PR, aim to preserve germplasm collections of cultivated tropical/subtropical germplasm of banana (Musa acuminata), plantain (Musa acuminata x M. balbisiana), cacao (Theobroma cacao), mamey sapote (Pouteria sapota), sapodilla (Manilkara zapota), species in the Annona and Garcinia genera, rambutan (Nephelium lappaceum), lychee (Litchi chinensis), longan (Dimocarpus longan), carambola (Averrhoa carambola), papaya (Carica papaya), and mango (Mangifera indica) through the introduction, maintenance, propagation, characterization and evaluation of these vegetatively propagated crops.

Technical Abstract:
The increase in ethnic diversity in the U.S., as well as changes in the diet habits of the public for health considerations, have opened a large market for tropical/subtropical fruits. Increased production of many tropical fruits, however, is hindered by a lack of basic information on how physiological, horticultural, environmental, entomological and pathological variables affect tropical fruit production systems and how these interact to influence yield and fruit quality. Promising germplasm of banana (Musa acuminata), mamey sapote (Pouteria sapota), papaya (Carica papaya), lychee (Litchi chinensis), longan (Dimocarpus longan), carambola (Averrhoa carambola), rambutan (Nephelium lappaceum), sapodilla (Manilkara zapota) and mangosteen (Garcinia mangostana) are being introduced by USDA-ARS and evaluated in collaboration with UPR-AES at various ecological zones in Puerto Rico for tolerance to pests and diseases, yield, acid soil tolerance, drought tolerance, nutrient use efficiency, and scion/rootstock compatibility. The development of a tropical fruit industry will allow for an expanded trade between the U.S. and other markets. The research conducted in this project directly impact producers in rural areas by providing growers in these regions with alternative high-cash crops and best management practices. Results from recent research conducted by USDA-ARS in Puerto Rico with these crops are discussed herein.